Method of calibrating a weighing apparatus within an enclosure

Abstract

A method for recalibrating an electronic scale mounted within an enclosure which includes a display and a plurality of switches set to a position representing the calibrated digital output of the scale when the scale is placed in a first and second weighted condition includes the steps of displaying the weight of the weighed condition of the scale, sampling the scale to generate digital signals outputted by the scale when the scale is placed in the first and second weighted condition, comparing the sampled digital signals with the digital signals represented by the setting of the switches, removing the scale from the enclosure when the sampled digital signals are within a predetermined value of the digital signals set up in the switches and displaying the new settings of the switches which corresponds to the sampled digital signals enabling the operator to set the switches accordingly.

We claim: 
     
       1. In a weighing system which includes a processor, a display connected to the processor, a calibrated scale mounted within an enclosure and outputting digital signals having a value representing the weight of an object placed on the scale and a plurality of first and second settable switches set to a position representing the first and second digital values outputted by the scale when a corresponding first and second weight is placed on the scale, a method for recalibrating the scale when mounted within the enclosure comprising the steps of: placing an object having a first weight on the scale to put the scale in a first weighted condition;   applying power to the system;   performing a first sampling operation of the output of the scale in response to the application of power to the system to generate a third digital value representing the output of the scale for said first weight;   comparing the third digital value with the first digital value;   displaying the first weight on the display when the third digital value is within a first predetermined value of the first digital value;   performing a second sampling operation of the output of the scale to establish a first average digital value outputted by the scale when the first weight is placed on the scale;   comparing the first average digital value with the third digital value;   removing the scale from the enclosure when the first average digital value is within the first predetermined value of the third digital value;   comparing the digital value represented by the setting of the first settable switches with the first average digital value;   displaying on the display the setting of the first settable switches to represent the first average digital value; and   setting the first settable switches in accordance with the setting displayed on the display.   
     
     
       2. The method of claim 1 in which the step of displaying the settings of the first settable switches include the step of assigning a position to each of the first settable switches from highest to lowest and displaying the lowest switch position of the remaining first settable switches to be changed. 
     
     
       3. The method of claim 1 in which the first weight of the object placed on the scale is 20 pounds. 
     
     
       4. The method of claim 1 in which the step of sampling the output of the scale to establish a first average digital value further includes the steps of: performing a third sampling operation of the output of the scale a predetermined number of times;   summing the number of sampled outputs of the scale;   dividing the sum by the predetermined number to obtain the first average digital value; and   storing the first average digital value.   
     
     
       5. The method of claim 1, also including the steps of: displaying instructions to place the scale in a second weighted condition in response to the establishment of the first average digital value;   placing the scale in a second weighted condition;   performing a third sampling operation of the output of the scale to generate a fourth digital value representing the output of the scale for the second weighted condition of the scale;   comparing the fourth digital value with the second digital value;   performing a fourth sampling operation of the output of the scale to generate a second average of the digital value when the fourth digital value is within a first predetermined value of the second digital value;   comparing the second average digital value with the third digital value; and   removing the scale from the enclosure when the second average digital value is within a second predetermined value of the third digital value.   
     
     
       6. The method of claim 4, also including the steps of: comparing the second digital value with the second average digital value;   displaying the setting of the plurality of second switches to represent the second average digital value; and   setting the plurality of second switches in accordance with the settings displayed on the display.   
     
     
       7. The method of claim 6 in which the second weighted condition of the scale is zero pounds. 
     
     
       8. The method of claim 5 in which the step of sampling the output of the scale to generate a second average digital value further includes the steps of: performing a fifth sampling operation of the output of the scale a predetermine number of times;   summing the number of sampled outputs of the scale;   dividing the sum by the predetermined number to obtain the second average digital value; and   storing the second average digital value.   
     
     
       9. In a weighing system which includes a processor, a display connected to the processor, a calibrated scale mounted within an enclosure and outputting a digital value representing the weight of a merchandise item positioned on the scale and a plurality of first and second settable switches set to a calibrated position representing first and second digital values, respectively, outputted by the scale when in a corresponding first and second weighted condition, a method for recalibrating the scale when mounted within the enclosure comprising the steps of: placing the scale in said first weighted condition;   applying power to the system;   performing a first sampling operation of sampling the output of the scale in response to the application of power to the system to generate a third digital value representing the output of the scale for said first weighted condition;   comparing the third digital value with the first digital value;   displaying the weight of said first weighted condition on a display when the third digital value is within a first predetermined value of the first digital value;   performing a second sampling operation of the output of the scale a predetermined number of times to establish an average third digital value outputted by the scale when the third digital value is within said first predetermined value of the first digital value;   displaying the weight of said second weighted condition on the display;   placing the scale in said second weighted condition;   performing a third sampling operation of the output of the scale in response to the displaying of the weight of said second weighted condition on the display to generate a fourth digital value;   comparing the fourth digital value with the second digital value;   performing a fourth sampling operation of the output of the scale a predetermined number of times to establish an average fourth digital value when the fourth digital value is within said first predetermine value of the second digital value;   comparing the average fourth digital value with the second digital value;   comparing the average third digital value with the first digital value;   removing the scale from the enclosure when the average fourth digital value is within a second predetermined value of the second digital value and the average third digital value is within a third predetermined value of the first digital value;   comparing the settings of the first and second plurality of settable switches with the third and fourth average digital values;   displaying the settings of the first and second plurality of settable switches to represent said third and fourth average digital values, respectively; and   setting the first and second plurality of settable switches in accordance with the settings displayed on the display.   
     
     
       10. The method of claim 9 in which the weight of the first weighted condition is 20 pounds and the weight of the second weighted condition is zero pounds.